Learn Russian: В отличие от старых мастеров, мне не о чем советоваться с этим пчеловодом. - Unlike the old masters, I have nothing to consult with this beekeeper about.

The base word here is нечего (there is nothing). When a preposition like о is needed, it splits the negative pronoun in two and sits directly in the middle. So, нечего + о becomes не о чем. Notice that the pronoun changes to the prepositional case чем to match the requirements of the preposition о.

Why is the sentence using the dative мне instead of the nominative я?

Constructions using negative pronouns like нечего or не о чем are impersonal in Russian. The person who experiences this lack of something must be in the dative case. The literal structure is that to me, there is nothing about which to consult.

Does the phrase в отличие от always take the genitive case?

Yes. The set phrase в отличие от means unlike or in contrast to, and the preposition от dictates that the following noun phrase must be in the genitive case. That is why we see старых мастеров (genitive plural) here.

Why do we use the imperfective verb советоваться here rather than the perfective посоветоваться?

When combined with negative pronouns like не о чем to express that there is absolutely no possibility or reason to do something, Russian heavily prefers the imperfective infinitive. It denies the action in general, rather than a single, specific instance of consulting.